[RFI] telephone rfi tidbits - Multiple Phones

Mon, 12 Nov 2001 20:25:59 -0500

Great info Dave, and thanks for sharing it.

Experience has also pointed out to us that if 'any one' phone on a multi
phone line is susceptible to Rfi, it tends to 'share' that Rfi with all
other phones due to the interconnections. Thus when testing out what phones
are causing/getting Rfi, disconnect all phones and test em one at a time.
Thus it could also be possible for a Rfi free phone to seem to be getting
Rfi that is actually coming from another phone else where on the same home
phone wiring.

73 from Bill - WD8ARZ

----- Original Message -----
From: "David O Hachadorian" <k6ll@juno.com>
To: <rfi@contesting.com>
Sent: Saturday, November 10, 2001 1:41 PM
Subject: [RFI] telephone rfi tidbits

> I had a neighbor complain of telephone rfi during a contest
> last weekend. My XYL took the usual step of handing out
> a Radioshack 43-591 phone, but for the first time ever, it
> didn't solve the problem.
> I got around to working with the neighbor yesterday,
> and, to make a long story short, the problem turned out to be
> her RCA Directv Satellite Receiver, which is always connected
> to the phone line. The receiver modem was actually rectifying the
> 20 meter RF and putting an extremely loud crackling noise, which
> didn't sound at all like the SSB test signal, onto her telephone
> line, wiping out all her phones and computer.
> I put a Radioshack telephone interference filter on the
> satellite receiver, and the problem was solved.
> Incidentally, Radioshack has lowered the price on these filters
> to $10.99 in their 2002 catalog. The filter attenuation curve
> and general appearance is identical to the K-Com unit, which
> sells for $16.95 plus shipping.
> In conducting the test, the XYL and I communicated
> using little Motorola Family Radio units that are available from
> Wal-Mart for $32 a pair. They worked great, and didn't experience any
> QRM from the 1500 watt transmitter. I just told the xyl when to
> transmit, and she pressed the play button on the voicekeyer.
> Dave Hachadorian, K6LL
> Yuma, AZ
> K6LL@juno.com